Semiconductor-package measuring method, measuring socket, and semiconductor package

ABSTRACT

Electrical connection of a measuring socket to an IC package, to measure electrical characteristics of the IC package, is realized by bringing a measuring pin of a measuring arm of the measuring socket into contact with an end surface of a distal end of a lead of the IC package. Accordingly, a problem of solder plated to the lead becoming attached to and deposited on an upper side of a socket pin and shaved off by the distal end of the lead, and thereby producing solder residue, is solved. This problem occurs when electrical connection to an IC package is conventionally realized by bringing the distal end of the lead of the IC package into contact with a distal end of the socket pin.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a semiconductor-packagemeasuring method for testing electrical characteristics of asemiconductor package by setting the semiconductor package individuallyinto a measuring socket in the semiconductor-package inspecting step, toa measuring socket of a semiconductor package, and to a semiconductorpackage to be tested.

[0003] 2. Description of the Related Art

[0004] Conventionally, the inspecting step of testing an IC package,which has been formed into an individual piece by molding the IC packageonto a lead frame with a mold resin and then soldering the package ontothe surface of the lead frame and lead-working the package, has beenmanually executed or automatically executed while the IC package wasautomatically carried. The inspecting step described below isautomatically executed.

[0005]FIG. 7 is a view showing a conventional IC-package measuringmethod, and is a schematic sectional view of a measuring device viewedfrom a side thereof.

[0006] A test tray 2 mounting an IC package 1 is transported by anot-illustrated transporting mechanism and the IC package 1 is set to aninspection position at which a socket 3 is disposed. In this case, theIC package 1 is positioned to a position at which the distal end of alead 4 of the IC package 1 contacts the distal end of a conductivesocket pin 5 of the socket 3.

[0007] Then, a lead-holding portion 7 made of an insulator and providedfor a lead holding mechanism 6 of the measuring device lowers from theupper side to lower the test tray 2 simultaneously with the IC package 1and bring the distal end of the lead 4 of the IC package 1 into contactwith an upper surface of the distal end of the socket pin 5.

[0008] The lead holding mechanism 6 stops at a position where themechanism 6 contacts a stopper 8 of a lead holder provided for thesocket 3. Thereby, the lead holding portion 7 stops at a positionfurther down by a certain distance from a position where the portion 7contacted the lead 4 of the IC package 1. A stroke of the lead holdingmechanism 6 from a position at which the lead holding portion 7 contactsthe inserted lead 4 of the IC package 1 to the stopper 8 is referred toas socket pushing distance B.

[0009] In this case, the lead 4 and socket pin 5 move from the positionshown by a continuous line to the position shown by analternate-long-and-short-dash line and the lead 4, socket pin 5, aconductive portion of the socket 3, and a contact 9 are electricallyconnected with a not-illustrated measuring device, and therebyelectrical characteristics are measured.

[0010]FIGS. 8A and 8B are enlarged views of the portion A in FIG. 7, inwhich FIG. 8A shows a case when the lead 4 and socket pin 5 are presentat the continuous-line position and FIG. 8B shows a case when the sameare present at the alternate-long-and-short-dash-line position.

[0011] Solder residue 10 is solder deposited on the socket pin 5 whenthe lead 4 is set to the socket pin 5 as shown in FIG. 8A, which solderwas used for solder-plating the surface of the lead 4 of the IC package1 in a previous step.

[0012] In the conventional IC-package measuring method described above,however, the deposited solder residue 10 is shaved off at the distal endof the lead 4 as shown in FIG. 8B during the stroke of the socketpushing distance B.

[0013] The shaved-off solder residue 10 attaches to the surface of thelead 4 or between a plurality of the leads 4 to cause a problem that theIC package 1 is mis-measured and the operating rate of the measuringdevice is lowered.

SUMMARY OF THE INVENTION

[0014] To solve the above problem, the present invention measureselectrical characteristics by bringing a measuring pin of a measuringarm of a measuring socket into contact with an end surface of a distalend of a lead of a semiconductor package.

[0015] In accordance with the present invention, because electricalcharacteristics are measured by bringing the measuring pin into contactwith an end surface of the distal end of the lead, no solder residue isproduced and thus IC packages are not mis-measured and the operatingrate of the measuring device is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a view showing a first embodiment of the presentinvention.

[0017]FIG. 2 is a view showing a measuring method of the firstembodiment.

[0018]FIG. 3 is a view showing a second embodiment of the presentinvention.

[0019]FIG. 4 is an enlarged view of the distal end of a lead.

[0020]FIG. 5 is a side view of a measuring socket of the secondembodiment of the present invention viewed from the direction of thearrow E in FIG. 3.

[0021]FIGS. 6A and 6B are views showing a third embodiment of thepresent invention.

[0022]FIG. 7 is a view showing a conventional IC-package measuringmethod.

[0023]FIGS. 8A and 8B are enlarged views of portion A of FIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024]FIG. 1 is a view showing the first embodiment of the presentinvention, and is a schematic sectional view of a principal portionincluding a measuring socket viewed from the side.

[0025] A seat 13 provided with a lead-receiving portion 12, forreceiving by point contact a bottom of a distal end of a lead of an ICpackage such as a semiconductor package, is provided at an end of ameasuring socket 11 made of synthetic resin.

[0026] A distal end of the lead-receiving portion 12 is formed as apoint, and the lead-receiving portions 12 (sockets to be electricallyconnected with measuring sockets for measurement) corresponds to anumber of leads to be tested.

[0027] Moreover, measuring arms 14 corresponding to the number of leadsto be measured are linearly arranged near the seat 13 and are rotatablysupported by a shaft 15.

[0028] The measuring arm 14 is formed of a conductive material in agentle L-shape as a whole, a hole is formed near a central portion ofthe arm 14, and the insulator shaft 15 is passed through the hole.

[0029] A convex measuring pin 16 such as a pin having an acute-angulardistal end is formed at one end of the measuring arm 14. When thelead-receiving portion 12 receives a lead, the distal end of themeasuring pin 16 is positioned so as to line-contact at a centralportion of an end surface of the lead in the thickness directionthereof.

[0030] Moreover, the measuring arm 14 is constantly urged by a spring 17such that the measuring pin 16 is kept separate from the distal end ofthe lead.

[0031] A rotational-mechanism portion 19 provided at a lead-holdingmechanism 18 of the measuring device contacts another end of themeasuring arm 14. When a distal end of the rotational-mechanism portion19 presses the other end of the measuring arm 14 downward, the measuringarm 14 rotates against the spring 17 with the shaft 15 serving as afulcrum.

[0032] A portion of the measuring arm 14 extended toward the other endof the arm 14 from a portion slightly separate from the shaft 15 of thearm 14 is formed to have a certain angle, and a contact such as a POGOcontact pin 20 is embedded in the measuring socket 11 and a board 21under this portion of the measuring arm 14.

[0033] POGO contacts 20 equal to the number of measuring arms 14 arelinearly arranged such that the bottom of each measuring arm 14 contactsand electrically connects with the head of each POGO contact pin 20.

[0034] The POGO contact pin 20 is connected to a measuring device usedto measure an electrical characteristic of the IC package, and it isalso possible to apply a contact probe to the pin 20.

[0035] A lead-holding arm 22 made of an insulating material is set atthe lead-holding mechanism 18. The lead-holding arm 22 is constituted soas to move downward, hold the distal end of the lead of the IC packagemounted on the test tray 2 together with the lead-receiving portion 12of the seat 13, and further move downward, while holding the lead, to anupper side of a stopper 23 set at the board 21.

[0036]FIG. 2 is a view showing a measuring method of the firstembodiment, and is a schematic sectional view of a principal portion ofthe measuring socket and the like to which the IC package is set, viewedfrom the side.

[0037] The test tray 2 on which the IC package 1 is mounted istransported by a not-illustrated transporting mechanism and the ICpackage 1 is set to an inspection position at which the measuring socket11 is disposed. In this case, the distal end of the lead 4 of the ICpackage 1 is positioned to a position corresponding to the measuring pin16.

[0038] Then, the lead-holding mechanism 18 lowers from the upper side,the distal end of the lead 4 is held by the lead-receiving portion 12 ofthe seat 13 formed at the measuring socket 11 and the lead-holding arm22, and the lead-holding mechanism 18 further lowers, while holding thedistal end of the lead 4, to the upper side of the stopper 23.

[0039] At this time, the distal end of the lead 4 point-contacts thelead-receiving portion 12.

[0040] When the lead-holding mechanism 18 lowers, therotational-mechanism portion 19 lowers in the direction of arrow C topress the end of the measuring arm 14 opposite to the end thereof atwhich the measuring pin 16 is formed.

[0041] Then, the measuring arm 14 rotates in the direction of arrow Dagainst the spring 17, using the shaft 15 as a fulcrum, and themeasuring pin 16 perpendicularly contacts the end surface of the distalend of the lead 4. The pointed distal end of the measuring pin 16line-contacts the central portion of the section of the lead 4 in thethickness direction thereof.

[0042] When the measuring arm 14 rotates, the bottom of the measuringarm 14 contacts the POGO contact pin 20, the lead 4 of the IC package 1and the POGO contact pint 20 are electrically connected through themeasuring pin 16 and measuring arm 14, and electrical characteristics ofthe IC package 1 are measured by a measuring device connected with thePOGO contact pin 20.

[0043] At this time, the measuring pin 16 contacts the end surface ofthe distal end of the lead 4. However, the lead 4 was cut byindividual-piece punching after solder-plating of the lead 4, and thusno solder remains on the end surface and no solder is transferred(attached) to or deposited on the measuring pin 16.

[0044] Moreover, because the lead-receiving portion 12 of thesynthetic-resin seat 13 receives the distal end of the lead 4 by pointcontact, no solder is attached to the seat 13.

[0045] As described above, according to the first embodiment, becauseelectrical characteristics are measured by bringing the measuring pin 16into contact with the end surface of the distal end of the lead 4, nosolder is attached to or deposited on the measuring pin 16 and no solderresidue is produced.

[0046] Therefore, no solder residue attaches to the surface of the lead4 or between the leads 4, no IC package 1 is mis-measured, and it ispossible to improve the operating rate of a measuring device.

[0047]FIG. 3 is a view showing the second embodiment of the presentinvention, and is a schematic sectional view of a principal portion of ameasuring socket and the like at which an IC package is set, viewed fromthe side.

[0048]FIG. 4 is an enlarged sectional view of a distal end of a lead ofan IC package and FIG. 5 is a side view of the second embodiment in FIG.3, viewed from the direction of arrow E, in which view measuring armsare omitted.

[0049] As shown in FIG. 4, a V-shaped groove 26 is formed at the bottomof the distal end of a lead 25 of an IC package 24.

[0050] As shown in FIG. 5, concave grooves 29 respectively having awidth into which the lead 25 can be inserted and corresponding to thenumber of the leads 25 are formed in a seat 28 formed at an end of ameasuring socket 27.

[0051] A lead-receiving portion 30 whose cross section is formed into anacute angle is set in the groove 29. As shown in FIG. 4, thelead-receiving portion 30 engages and line-contacts with the V-shapedgroove 26 formed at the bottom of the distal end of the lead 25.

[0052] As shown in FIG. 5, a distal end 32 of a lead-holding arm 31 ofthe lead-holding mechanism 18 is formed into a convex shape so as tocorrespond to the concave shape of the groove 29 of the seat 28 andfunctions so as to hold the distal end of the lead 25 by thelead-receiving portion 30 and the distal end 32.

[0053] Other structures are the same as those of the first embodiment,and the measuring method is the same as in the first embodiment exceptthat the distal end of the lead 25 is held by the convex distal end 32of the lead-holding arm 31 and the lead-receiving portion 30 of the seat28, and the V-shaped groove 26 of the lead 25 engages with thelead-receiving portion 30. Therefore, descriptions of the otherstructures are omitted.

[0054] According to the second embodiment as described above, inaddition to the advantages of the first embodiment, the lead 25 isprevented from bending toward an the IC package side when the measuringpin 16 is pressed and the measuring arm 14 is rotated to bring the pin16 into contact with an end surface of the lead 25, because a pressureapplied to the distal end of the lead 25 is controlled by the V-shapedgroove 26 and lead-receiving portion 30.

[0055]FIGS. 6A and 6B are views showing the third embodiment of thepresent invention, and FIG. 6A is a top view of the IC package and FIG.6B is an enlarged top view of a portion F in FIG. 6A at which portionsof a seat and a measuring pin are added.

[0056] A distal end of a lead 34 of an IC package 33 is cut when thedistal end of the lead is worked after solder-plating. An end surface ofthe distal end is formed into a concave shape such as the V-shape shownin FIG. 6B.

[0057] Moreover, a measuring pin 35 of the measuring arm is formed intoa convex shape such as a reversed V-shape so as to engage an end surfaceshape of the distal end of the lead 34.

[0058] Other structures are the same as those of the second embodiment.

[0059] When the distal end of the lead 34 of the IC package 33 is set ata lead-receiving portion 30 of the seat 28, the same as in the secondembodiment, a reversed V-shaped portion of the measuring pin 35 contactsa V-shaped portion formed in the end surface of the distal end of thelead 34 and is pressed to be electrically connected, and electricalcharacteristics of the IC package 33 are measured.

[0060] Thus, by forming the end surface of the distal end of the lead 34into a concave shape and the distal end of the measuring pin 35 into areversed V-shape, a position of the lead 34 is corrected by the distalend of the measuring pin 35 even if the IC package 33 is slightlyshifted from a predetermined inspecting position while it istransported.

[0061] Moreover, because no solder is present on the end surface of thedistal end of the lead 34, no solder residue is produced.

[0062] According to the third embodiment as described above, in additionto the effect of the second embodiment, because the shape of the endsurface of the distal end of the lead 34 and that of the distal end ofthe measuring pin 35 are formed so that they are easily engaged witheach other, a position of the lead 34 is corrected by the distal end ofthe measuring pin 35 and the lead 34 thereby securely contacts themeasuring pin 35 and proper measurement can be performed.

What is claimed is:
 1. A method for measuring a semiconductor package bysetting the semiconductor package at a measuring socket, wherein ameasuring pin of a measuring arm of the measuring socket contacts an endsurface of a distal end of a lead of the semiconductor package, andelectrical characteristics of the semiconductor package are measured. 2.A method for measuring a semiconductor package having a lead having adistal end portion, by setting the package at a measuring socket, themethod comprising the steps of: transporting the semiconductor packageto the measuring socket; setting the distal end portion of the lead at apredetermined position; pressing the distal end portion of the lead froman upper side thereof; and measuring electrical characteristics of thesemiconductor package, wherein the measuring socket has (1) a leadholding mechanism having a rotation mechanism portion, (2) a measuringarm having a first end portion and a second end portion, the first endportion having a measuring pin and (3) a contact portion electricallyconnected to an external section, and, in the step of pressing thedistal end portion of the lead, the lead holding mechanism presses thedistal end portion of the lead, at which time the rotation mechanismportion causes the measuring arm to rotate such that the measuring pincontacts an end surface of the distal end portion of the lead and thesecond end of the measuring arm contacts the contact portion.
 3. Ameasuring socket for a semiconductor package, the measuring socketcomprising: a seat provided with a lead receiving portion for receivinga bottom of a distal end portion of a lead of the semiconductor package;conductive measuring arms equal in number to a number of leads that areto be used for measurement of the semiconductor package, the measuringarms being linearly arranged and rotatably supported by a pivot which isan insulator, and each measuring arm having formed at one end thereof ameasuring pin with a convex cross-section and each measuring arm beingprovided such that when measurement is not being performed the measuringpin is urged away from the distal end portion of the lead and at a timeof measurement another end of the each measuring arm is lowered suchthat the each measuring arm rotates about the pivot and the measuringpin contacts an end surface of the distal end portion of the lead; andcontacts equal in number to the measuring arms, which contacts arelinearly arranged and are contacted by the measuring arms and conductelectricity when the measuring arms are rotated at a time ofmeasurement.
 4. The measuring socket according to claim 3, wherein themeasuring pin has an angular cross section in a horizontal direction. 5.The measuring socket according to claim 3, wherein the measuring pin hasa convex cross section in a vertical direction.
 6. A measuring socketfor a semiconductor package, the socket comprising: a seat at whichrecessed grooves equal in number to a number of leads that are to beused for measurement of the semiconductor package are formed, the seatbeing provided and the lead receiving portion being formed in a acuteangular shape for engaging with a V-shaped groove formed in a bottomportion of a distal end portion of a lead of the semiconductor package;conductive measuring arms equal in number to the number of leads thatare to be used for measurement of the semiconductor package, themeasuring arms being linearly arranged and rotatably supported by apivot which is an insulator, and each measuring arm having formed at oneend thereof a measuring pin with a convex cross-section an eachmeasuring arm being provided such that when measurement is not beingperformed the measuring pin is urged away from the distal end portion ofthe lead and at a time of measurement another end of the each measuringarm is lowered such that the each measuring arm rotates about the pivotand the measuring pin contacts an end surface of the distal end portionof the lead; and contacts equal in number to the measuring arms, whichcontacts are linearly arranged and are contacted by the measuring armsand contact electricity when the measuring arms are rotated at a time ofmeasurement.
 7. The measuring socket according to claim 6, wherein themeasuring pin has an angular cross section in a horizontal direction. 8.The measuring socket according to claim 6, wherein the measuring pin hasa convex cross section in a vertical direction.
 9. A semiconductorpackage having a lead in which a V-shaped groove is formed at a bottomportion of a distal end of the lead, wherein the V-shaped groove engageswith a lead-receiving portion which is formed at a seat of asemiconductor package measuring socket, and the lead receiving portionhas an acute angular cross section.
 10. A semiconductor package having alead with a distal end portion whose end surface is formed into a convexshape in a vertical direction, wherein the distal end of the leadengages with a measuring pin formed at a measuring arm of asemiconductor package measuring socket, and the measuring pin has aconvex cross section in the vertical direction.